Magnetic disk devices are commonly used in electronics devices needing storage, such as large computers, work stations, personal computers, etc. These devices are becoming more and more important, and developments toward greater capacity and smaller size are being sought. Increased density is essential for increasing the capacity of magnetic disk devices and making these devices more compact.
One method of increasing the density of magnetic disk devices involves a decrease in the medium noise caused by reducing the magnetization inversion units of the magnetic recording medium. Conventional magnetic recording media employ a structure in which the ferromagnetic crystal grains which form the magnetic recording layer are separated by a non-magnetic material which is already contained in the magnetic recording layer.
One attempt for enhancing density by controlling these non-magnetic materials involves discrete track media (DTM) in which processing is carried out in order to provide separation between recording tracks, and also bit patterned media (BPM) in which processing is carried out in order to provide separation between recording bits, and in both cases the technology for forming separating regions is an important factor in increasing the density.
One type of magnetic film processing in which a magnetic film is physically processed by etching or the like has been attempted as a method for producing DTM. Magnetic film-processed DTM are generally produced by the following processes: (1) a metal thin film is provided on the recording layer and a resist is applied; (2) a micropattern is applied to the resist by lithography technology or the like; (3) the metal thin film in the recesses of the resist pattern is etched via a dry process, and the recording layer is exposed; (4) the exposed recording layer is etched via a dry process, and recording track separating parts (grooves) are formed; (5) the residual resist and metal thin film in the recording tracks (lands) are removed. (6) The groove areas are back-filled with a non-magnetic material and planarized. (7) A protective layer and a lubricant layer are applied. Various types of research and development are currently being carried out in order to improve the precision of each process.
Various production methods have been proposed in relation to the back-filling and planarization process, and oxides, nitrides, carbides, and borides are generally used therein. Japanese Unexamined Patent Application Publication No. H9-97419 proposes a method in which the separating regions comprise oxides such as SiO2, Al2O3, TiO2; nitrides such as Si3N4, AlN, TiN; carbides such as TiC; and borides such as BN; or polymeric compounds based on any of C, CH, and CF; furthermore, Japanese Unexamined Patent Application Publication No. 2000-298822 proposes a method in which the separating regions nitrides comprise oxides such as SiO2, Al2O3, TiO2; nitrides such as Si3N4, AlN, TiN; carbides such as TiC; and borides such as BN; and polymeric compounds based on any of C, CH, and CF.
Furthermore, Japanese Unexamined Patent Application Publication No. 2009-080902 suggests some metal nitrides, such as C, Si, Ti, V, Cr, Ni, Cu, Ga, Y, Zr, Nb, Mo, Hf, Ta, W, and Al, or alloys thereof.
In addition, Japanese Unexamined Patent Application Publication No. 2008-159146 discloses back-fill materials comprising oxides, nitrides, and borides, in addition to Al, Ti, Cr, and Cr alloy, NiTa, TiOx, Al2O3, Ru, and Ta, for example, but there is no reference to effects or modes of embodiment.